This invention relates to apparatus for cleaning a drain pipe or waste line and, more particularly, to hand held apparatus for feeding a flexible snake into a waste line and rotating the snake so as to clear an obstruction or blockage in the line.
The present invention finds particular utility in connection with portable motor driven flexible snake-type drain cleaning apparatus of the character in which the snake is clamped during feeding and is rotated by a hand held, trigger actuated motor, such as shown for example in U.S. Pat. Nos. 3,691,583 to Silverman et al. and 4,218,802 to Babb et al. Accordingly, the invention will be described in detail hereinafter in conjunction with such apparatus. At the same time, however, it will be appreciated that the invention is applicable to other drain cleaning apparatus in which a clamping arrangement is provided to hold the snake against axial displacement relative to the apparatus during movement of the snake into and out of a waste line.
Typically, such drain cleaning apparatus of the character disclosed in the above patents is comprised of a hand held, trigger actuated motor drivingly connected to a housing for rotating the housing about a longitudinal axis. The housing is provided with a guide tube opening thereinto coaxial with the axis of rotation and through which extends a flexible snake which is coiled within the housing or in a snake cartridge removably supported in the housing for rotation therewith. As shown in the patent to Silverman et al., the snake cartridge can be removable to facilitate connecting successive snakes for feeding into a waste line, or for using different diameter snakes with the apparatus. The snake, as is conventional, is an elongate, flexible member made of tightly wound spring wire, and the end thereof extending through the guide tube is adapted to be manually pulled from or pushed back into the housing where it is stored during periods of non-use. A hand grip sleeve arrangement surrounds the guide tube and is rotatable and axially displaceable relative thereto to effect the displacement of snake clamping elements into engagement with the snake to preclude axial displacement of the snake relative to the guide tube and housing during displacement of the rotating snake into a waste line. The clamping elements also apply additional holding force to preclude rotation of the snake relative to the guide tube during the drain cleaning operation.
Apparatus of the foregoing character heretofore provided have been comprised primarily of metal parts, whereby replacement of certain parts of the apparatus is frequently required as a result of the corrosive nature of the liquid and solid waste materials encountered by the snake during use of the apparatus. Moreover, snake clamping arrangements such as that shown in the patent to Babb et al. are structurally complex and expensive and, while the spring finger snake gripping arrangement shown in the patent to Silverman et al. provides a more economical approach, the component parts in the Silverman et al. apparatus are adversely affected by corrosion and undesirably stressed during use, thereby promoting frequent replacement of the spring finger elements. More particularly in this respect, the snake gripping spring fingers in the patent to Silverman et al. are secured to the metal guide tube by threaded fasteners which, as the result of corrosion, can break or otherwise become extremely difficult if at all possible to remove in connection with replacing the spring fingers. Furthermore, the threaded fastener in the Silverman et al. arrangement extends through an opening in the spring finger element which is immediately adjacent the bending point for the spring finger, whereby considerable stress is placed on the spring finger both at the bending point and at the point of connection which is weakened by the opening for the fastener. It will be appreciated that both of these factors disadvantageously affect the fatigue life of the spring finger element.